Improvement in valve-gear for reversing



Patented Aug'.1-5,1876.

. W. H. DOWNING.

VALVE-GEAR FOR REVERSING.

WIT NEE5ES= MIA/AM N FEYERS. FHOTWLITNOGRAPHER, WASHINGTON. D C.

l l T 4 cylinder and R the steamchest.

UNITED STATES PATENT OFFICE.

WILLIAM H. DOWNING, OF BARNHARTS MILLS, PENNSYLVANIA.

IMPROVEMENT IN VALVE-GEAR FOR REVERSING.

Specification forming part of Letters Patent No- 3 81.153, dated August15, 1876; application filed June 20, 1876.

To all whom it may concern:

Be it known that 1, WILLIAM H. DOWNING, of Barnharts Mills, in thecounty of Butler and State of Pennsylvania, have invented certain newand useful Improvements in Valves; and I do hereby declare the followingto be a full, clear, and exact description of the invention, such aswill enable others skilled in the art to which it pertains to make anduse it, reference being had to the accompanying drawings, which formpart of this specification.

The nature of my invention consists in the construction and arrangementof a balanced valve and reverse-gear for steam-engines, as will behereinafter more fully set forth.

In the annexed drawings, which fully illustrate my invention, -Prepresents the steam- A is the valve seat, provided with the steam inletports a a and exhaust-port b, as shown. The valve consists of two disks,B and O,of unequal diameter, connected in the center so as to form asteam space or chamber, d, between them; or the valve may be made in onesolid piece, constructed to form the two disks and steamspace. The disk0- is the larger one, resting on the seat A, and has steam-ports 'eethrough it, and exhaust-passages ff on its face side. The smaller disk Bhas a circumferential groove turned in it to receive metal packing ringsD. When the valve is in its place in the steam-chest R, which is turnedof diiferent diameter, to correspond with the size of the two disks,steam enters through the inlet E into the chamber or space d between thetwo disks. If the disks were of the same size, and no steam allowed topass by either disk, the valve would not be forced either way. But asthe disk 0 has the steam-ports e c, this end of the valve would have tobe made as much larger as the area of said openings, and the valve wouldthen balance, as there would be no more pressure one way than the other;but when the engine makes a revolution, the exhaust steam passes by theface of the valve at f, and out of the exhaust-port b. In passing theface of the valve, the exhaust steam will press the valve from its seat,and, hence, the disk 0 must be madelarge enough to counter act thispressure by the steam-pressure in the spaced.

In large engines, or in small engines also, if necessary, the exhauststeam is passed through a passage, F, to the back of the disk B, tocounterbalance the exhaust-pressure on the face of the valve; and inthat case a valve, G, is used to regulate the pressure on the back ofthe disk B. From the back of the valve project four pins, H H, as shown,

which pins, in a full-sized valve, will be provided withfriction-rollers. S is the valve-rod, provided with two eccentric or camprojections, I I, which are formed substantially as shown, and placedbetween the pins H. The valve-rod S is, by a swivel-joint, J, connectedto the eccentric-rod V, operated in the usual manner by the eccentric L.0n the valve-rod S is feathered a lever, K, held in a-suitable arm orstandard, through which the valve-rod passes, and said lever is to beheld in a notched or ratchet bar, W. When the lever is set in the centernotch, the valve will not move, the cams I I passing freely between thepins H H; but when moved either way from that point, the cams I willoperate on the pins H, and rotate the valve suiiiciently to uncover thesteam-ports a a, and thus start the engine either backward or forward,as the cam L may be set.

N is the cap of the steam-chest, in the center of which is a set-screw,O, to keep the valve down on its seat.

Having thus fully described my invention, what I claim as new, anddesire to secure by Letters Patent, is-

The combination of the valve B G, having pins and rollers H, the cam oreccentric projections I I on the valve-rod S, and the operating-lever K,attached to said rod, all substantially as and for the purposes hereinset forth.

In testimony that I claim the foregoingI have hereunto set my hand this13th day of June, 1876.

WILLIAM H. DOWN IN G.

Witnesses O. O. CRANE, ALEXANDER PETERS.

